Circuit breakers are an important part of the electrical infrastructure and of electrical systems and are used in any relatively large (low-voltage) energy distribution. Low-voltage energy distribution and low-voltage technology are used to mean electrical installations and circuits for voltages of up to 1000 volts AC or 1500 volts DC. In this case, circuit breakers such as, in particular, air circuit breakers or molded case (low-voltage) circuit breakers are used particularly often.
In the sense of the application, circuit breakers are used to mean, in particular, circuit breakers with an electronic trip unit.
The failure of a circuit breaker, in particular an air circuit breaker, may mean a large amount of financial damage. For example, production downtimes result, office buildings are without energy, elevators get stuck, ventilation systems fail and so on. The aim is therefore to provide a circuit breaker which has as little failure time as possible or no failure time. One measure for this are circuit breakers in which the electronic trip unit can be exchanged. That is to say, the trip unit can be exchanged by the operator or a service engineer in the event of an electronic fault.
The problem here is that system-specific protection parameters, so-called data specific to the trip unit, such as current limit values, tripping times, protection parameters, communication parameters, counter values, threshold values and the like, are adjusted to each trip unit of a circuit breaker. These must be individually adjusted to the device. If the trip unit is exchanged, they must be set again in the new trip unit in order to be compatible with the electrical system or the electrical circuit and its connected loads or further protective devices such as further downstream circuit breakers. In practice, this is associated with a considerable amount of effort.
Comprehensive paper documentation which is difficult to handle in practice has previously been kept and used for this purpose.
As a further alternative, systems were constructed in a redundant manner, with the result that it is possible to change over to the redundant system or installation in the event of a defect. However, this method is very cost-intensive and is therefore used only in high-availability systems.